I just signed up for a 2 day trial on pornhub. As soon as I gave then my info and pressed continue I was immediately charged for a full membership. I called there support line within 20 minutes and was told I would be charged for 1 month because a check box that signs you up for a full membership was selected by default. It is a shame that companies like this feel the need to trick customers to make a buck.
Proceed with extreme caution.